The map's letters do not sit alike on every icon: on the message icons'
sheet, X's and Y's are about 1.7 texels lower on their ovals than the
redraws put them. tools/button_assets.py layout now moves each icon's
letter (and Y's shadow, given the id "shadow") to where it best matches
the map's, and buttons.json keeps the move; the menus' large buttons move
by under 0.03 texels, the message icons' by up to 1.7. The PNGs are drawn
again, the sheet with all 256 levels of alpha rather than 32.
hud_hires_sprites_drawable read display.high_res_hud and high_res_text
only once, and hud_hires_sprite_bitmap kept its answer for the bitmap's
address, so turning either setting off or on left the message icons as
they were: both check again when the settings change, as
hud_hires_override_find does. ui_widget.c declares hud_hires_sprite_bitmap
with the port's other functions instead of in the block that calls it.
AUTHORS.md credits saulob for the redraws.
Checked with button_assets.py check against ui.map and side by side with
the map's icons; ninja linux and ninja android build, and the harness and
test_linux_port pass.